FOUS11 KWBC 170856
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
356 AM EST Sat Jan 17 2026

Valid 12Z Sat Jan 17 2026 - 12Z Tue Jan 20 2026

...Great Lakes... Days 1-3...

Shortwave trough passages in persistent cyclonic flow through the
Great Lakes will favor rounds of lake effect snow for at least the
next week.

A long wave trough over the western Lakes this morning will slowly
shift east through tonight. Northerly flow over Lake Superior will
bring LES to the western U.P. with westerly flow over the L.P.
where Day 1 snow probs for >6" are 40-60% in narrow snow belts.

The next reinforcing trough moves in from the west with NWly flow
bringing more snow to the western U.P. and most of the L.P. western
shore. SWly flow over Lake Erie pushes some single banding into
Buffalo, NY. These areas have Day 2 snow probs for >6" in the
20-60% range. Then the next shortwave trough moves in from the west
Monday night with LES until ridging builds briefly late Tuesday.
Day 3 PWPF for >6" is over the eastern U.P. on westerly flow along
with the northern L.P. Most notably however, is single banding in
westerly flow over Lakes Erie and Ontario with Day 3 PWPF for >6" 40-80%.

...Ohio Valley, Appalachians, and the Northeast... Day 1...

Arctic cold front will shift east from the Midwest this morning and
cross PA this afternoon. Snow squalls could accompany this front
mainly over Ohio and western PA/NY which are highlighted in ongoing
Key Messages that are linked below.

A SWly jet stream strengthens in place over the eastern U.S.
through tonight as a very positively-tilted trough shifts down the
Plains and pivots over the Mid-South. Downstream of this trough
will be expanding snow through the interior Northeast, especially
over the Poconos, Catskills, Berkshires and southern Green
Mountains just ahead of the cold front. Snow could exceed 1"/hr in
these areas per the 00Z HREF. This precip clears eastern Maine
this evening. Day 1 WPC probabilities for >4" are 50% in the Mohawk
Valley of NY and over the southern Greens, Whites, and eastern
Maine with 20-30% probs over the Poconos/Catskills, and Berkshires.

...Southeast, Mid-Atlantic, Northeast... Days 2-3...

Within the active pattern in the East is a southern portion of the full-latitude trough that swings through the Lower MS Valley
early Sunday. This will bring colder temperatures to the Southeast
as precipitation is slowly moving through the region along/behind
the front. Models are in better agreement tonight allowing enough
cold air in before precipitation ends to allow some light snow from
northern FL through the Carolinas Sunday morning with a dusting to
half an inch.

Further up the coast, precipitation will expand northeastward in
the right entrance of the >160kt jet atop marginal to cold
temperatures (milder along/east of I-95 in the Mid-Atlantic).
Elongated baroclinic zone and areas of surface low pressure will
lift northeastward just off the Mid-Atlantic/Northeast coast
Sunday night. Models have struggled here with the westward QPF
extent and are sensitive to the timing/strength of
upstream/incoming mid-level systems as the flow remains wide open.
For now, have remained fairly steady on the amounts which should
result in a swath of a few inches of snow from the Mid-Atlantic
into the NYC area and New England. 10 to 20% probs for >4" in Day 2 are
limited to eastern Maine and southeastern New England. The Day 2
swath of >2" over 10% extends south through NJ into the Delmarva.

...Central High Plains... Days 2/3...

Another Arctic cold front plunges down the Plains tonight through
Sunday. This banks cold air over the High Plains/against the front
ranges of the Rockies ahead of a reinforcing shortwave trough that
shifts down the Rockies Sunday night through Monday. Right entrance
jet dynamics over the existing front will allow banded snow to
develop over central MT/WY Sunday night with what appears to be the
main banding early Monday from northern CO terrain through western
KS. The WNWly orientation of these bands is parallel to flow and
should allow for persistence of moderate to locally heavy narrow
bands of snow. As of now Day 2.5 snow probs for >2" are around 20%
along the KS/CO border, but that is likely to increase as the
system gets closer. The ECAIFS was featuring this precip two nights
ago and global physical models are finally catching up. A risk for
4" or more is possible in these persistent banding scenarios.

Jackson

...Winter Storm Key Messages remain in effect and are linked below...

https://www.wpc.ncep.noaa.gov/key_messages/LatestKeyMessage_1.png

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